We investigate optimal metrological protocols for phase estimation in the presence of correlated dephasing noise, including spin-squeezed states sensing strategies as well as parallel and adaptive protocols optimized using tensor-network based numerical methods. The results are benchmarked against fundamental bounds obtained either via a latest quantum comb extension method or an optimized classical simulation method. We find that the spin-squeezed offer practically optimal performance in the regime where phase fluctuations are positively correlated, but can be outperformed by tensor-network optimized strategies for negatively correlated fluctuations.
@article{arxiv.2511.07211,
title = {Optimal phase estimation in the presence of correlated dephasing},
author = {Srijon Ghosh and Arkadiusz Kobus and Stanisław Kurdziałek and Rafał Demkowicz-Dobrzański},
journal= {arXiv preprint arXiv:2511.07211},
year = {2025}
}